Metal oxide catalysts may be used in a wide variety of chemical reactions including, but not limited to, elimination of carbon monoxide, decomposition of organic contaminants, bio-based production (e.g., biodiesel production), or combinations thereof. A feed stream, reaction products, or both, may include water. Water may deactivate a metal oxide catalyst, solubilize the metal oxide catalyst, or both. Activation of deactivated catalyst, separation of catalyst from reaction products, or both, may be costly and time intensive.